:I bought some rats about a month ago and I have fed them mainly on dog food and they seem to have gotten smaller. I dispatched one and looked at him, he was skin and bones!
Barring that you didn't wean them too fast or something I would think they caught a virus that is causing them to waste away. Are they all losing weight? Are they hunched over and puffy eyed or breathing heavily. I mostly think of this as I had something similar go through my mice and it was a pain. Some got it and wasted away and some never seem affected. Darwinism. Sonya